In 1830, R.Hirsch became rabbi of Oldenburg and in 1846, district rabbi of Moravia. In 1851, disturbed by assimilationist tendencies of the Jewish community, R.Hirsch was invited to be the rabbi of Frankfurt-on-Main. He erected Jewish schools and mikvaot (ritual baths) and institutions for ritual slaughter.

As a pulpit rabbi, wore clerical robes, accepted a choir (male-only), delivered sermons in German, the vernacular, and encouraged study of the Bible instead of engaging in pilpul (Talmudic "hairsplitting").

Under the pseudonym of "Ben Uziel" he wrote Neunzehn Briefe uber Judenthum (The Nineteen Letters of Ben Uziel), which was a brilliant defense of traditional Judaism in German, something that had not existed before it was published in 1836. In 1838, he published Choreb, a rationalist explanation of the 613 commandments. R.Samson Raphael Hirsch also published a commentary to the Torah, which exemplified his exegetical approach.

R. Hirsch was both a modernist and a traditionalist. His community became known as a model for communities strict in adherance to halakha, hence the term "neo-Orthodoxy." In his work, The Nineteenth Letters of Ben Uziel, he remarked that it would have been better for the Jews not to have been emancipated if the price to pay was assimilation.

R. Hirsch had no tolerance for the historical approach to Judaism (then an emerging school under Zecharia Frankel and the forerunner of the Conservative movement) as he felt it produced a relativistic attitude toward Torah. He fully believed in the total Divinity of the Torah and rejected the idea that law could be changed as a conscious process of historic development.

R. Hirsch's understanding of modern Judaism became known as "Torah im Derekh Eretz," after the verse in Pirke Avot (2:2) that "Torah is good together with derekh eretz." In the context of the Mishna, derekh eretz means an occupation but R. Hirsch expanded its meaning to include full engagement with western culture, while maintaining adherence to Jewish law. In this, he created the idea of the "Israel-Mentsch," the enlightened religious personality. While he believed that style or non-halakhic externalities could be changed, he believed that the essence of Jewish law and belief could not change.

R.Hirsch speaks of the ideal Jew both as a believer in the divine authority of the Torah as the mantle of eternal values as well as a cultured person belonging to the modern world. He rejected the pilpul (hairsplitting dialectic) method of Talmudic study, instead arguing that Torah study must reflect the view that the Torah is the divine guide to achieving the ennoblement of the human spirit. He argued that the Jews have a divinely ordained role to play in the world, which requires both Jewish education and a role in the modern secular world. Despite these enlightened views, R. Hirsch was a direct opponent of Reform, which had abolished all vestiges of ritual Judaism including the Sabbath, dietary laws, and garb. In the Nineteen Letters Hirsch wrote:

"Was Judaism ever 'in accordance with the times?' Did Judaism ever correspond with the views of dominant contemporaries? Was it ever convenient to be a Jew or Jewess?… Was that Judaism in accordance with the times, for which, during the centuries following the Disperson, our fathers suffered in all lands, through all the various periods, the most degrading oppression, the most biting contempt, and a thousand-fold death and persecution? And yet we would make it the aim and scope of Judaism to be always 'in accordance with the times!'"

Yet, despite R. Hirsch's passion for traditional Judaism, his congregations were made up of a diverse cross-section of cultured society - bankers, professors, physicians, artists, scientists and others who were both comfortable in Western society and observant in their own daily lives, thus proving that Torah and secular society do not conflict.